The present invention relates to improvements in apparatus for locating or detecting, engaging and transporting the leaders of convoluted webs of paper or the like, e.g., cigarette paper, tipping paper or other strip-shaped materials which are used in the tobacco processing industry. More particularly, the invention relates to improvements in apparatus which can be used to separate the leaders from the adjoining convolutions of webs which form rolls or bobbins and wherein the leaders are bonded or otherwise secured to the adjoining convolutions, and to thereupon transport the separated leaders to a splicing mechanism wherein a freshly delivered leader is attached to the trailing end of the running web which forms part of an expiring roll so that the running web can entrain the leader into the wrapping mechanism of a cigarette maker, into the tipping unit of a filter tipping machine, into the wrapping mechanism of a filter rod making machine, to a selected station of a packing machine, or to any other station where a continuous web or strip of paper, foil or the like is used for the making of rod-shaped smokers' articles, for the packing of such articles, or for other purposes. Still more particularly, the invention relates to improvements in apparatus of the above outlined character wherein the leader of the web is engaged by tongs or by a similar tool for transport along a predetermined path as soon as the leader is separated from the adjoining portion of the convoluted web.
Commonly owned U.S. Pat. No. 4,245,795 to Ludszeweit et al. discloses an apparatus which is used to splice the leaders of fresh rolls of cigarette paper or the like to the trailing portions of expiring rolls and comprises means for transporting a freshly separated leader from the respective roll to the splicing mechanism. The apparatus employs a cutter which is moved in parallelism with the axis of a fresh roll to sever the outermost convolution and to thus establish or form a leader which is thereupon transported to the splicing station by suction.
A similar apparatus is disclosed in commonly owned German Offenlegungsschrift No. 32 15 355 which proposes to use a tongue-like implement as a means for penetrating between a pair of neighboring convolutions close to the periphery of a fresh roll and preparatory to severing of the thus separated outermost convolutions and subsequent clamping of the thus obtained leader for transport to the splicing station.
In accordance with a further prior proposal by the assignee of the present application, the severing tool cooperates directly with tongs which serve to engage the thus obtained leader for transport to the splicing mechanism.
Conventional apparatus exhibit the drawback that one or more outermost convolutions of the web must be severed in order to provide or form a leader which is ready to be transported to the splicing station upon removal of the severed convolution or convolutions. The severing operation is a discrete step which precedes clamping of the thus formed leader by tongs or by a similar mechanism preparatory to transport toward the splicing mechanism. Moreover, the severed convolution or convolutions constitute waste and must be gathered and disposed of at frequent intervals. Still further, the operation of the aforedescribed apparatus is unduly affected even by relatively minor deviations of the shape and/or position or orientation of a fresh roll from an optimum shape and/or position or orientation.